Examples of methods for recovering gold contained in gold-containing metal sulfide ores include those described in Patent Literatures 1 and 2.
The methods described in these Patent Literatures 1 and 2 include: firstly, using an acidic leachate containing chloride ions and/or bromide ions as an anion and copper and iron as a cation to leach gold from a gold-containing metal sulfide ore into the acidic leachate while warming, then adsorbing the gold in the acidic leachate on activated carbon; and, thereafter, eluting the gold adsorbed on the activated carbon with an alkali liquid. Such gold recovery methods enable inexpensive and efficient recovery of gold contained in metal sulfide ores.
Activated carbon after having been used as an adsorbent which temporarily adsorbs gold in an acidic leachate in such a gold recovery method has a lowered activity, and thus must be regenerated for repeated use in adsorption of gold once again.
Regeneration treatment of used activated carbon typically includes heating used activated carbon at a temperature of about 250° C. in a non-oxidizing atmosphere for reactivation thereof, what is called, activation treatment, thereby recovering the adsorption performance of the used activated carbon as described in Patent Literatures 3.